/*
 * $Header: /l/extreme/cvspub/XPP3/java/src/java/xpath/org/xmlpull/v1/builder/xpath/jaxen/NamespaceContext.java,v 1.1 2004/06/16 15:55:34 aslom Exp $
 * $Revision: 1.1 $
 * $Date: 2004/06/16 15:55:34 $
 *
 * ====================================================================
 *
 * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions, and the disclaimer that follows 
 *    these conditions in the documentation and/or other materials 
 *    provided with the distribution.
 *
 * 3. The name "Jaxen" must not be used to endorse or promote products
 *    derived from this software without prior written permission.  For
 *    written permission, please contact license@jaxen.org.
 * 
 * 4. Products derived from this software may not be called "Jaxen", nor
 *    may "Jaxen" appear in their name, without prior written permission
 *    from the Jaxen Project Management (pm@jaxen.org).
 * 
 * In addition, we request (but do not require) that you include in the 
 * end-user documentation provided with the redistribution and/or in the 
 * software itself an acknowledgement equivalent to the following:
 *     "This product includes software developed by the
 *      Jaxen Project (http://www.jaxen.org/)."
 * Alternatively, the acknowledgment may be graphical using the logos 
 * available at http://www.jaxen.org/
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * ====================================================================
 * This software consists of voluntary contributions made by many 
 * individuals on behalf of the Jaxen Project and was originally 
 * created by bob mcwhirter <bob@werken.com> and 
 * James Strachan <jstrachan@apache.org>.  For more information on the 
 * Jaxen Project, please see <http://www.jaxen.org/>.
 * 
 * $Id: NamespaceContext.java,v 1.1 2004/06/16 15:55:34 aslom Exp $
 */


package org.xmlpull.v1.builder.xpath.jaxen;

/** Resolves namespace prefixes to namespace URIs.
 *
 *  <p>
 *  The prefixes used within an XPath expression are
 *  independant of those used within any target document.
 *  When evaluating an XPath against a document, only
 *  the resolved namespace URIs are compared, not their
 *  prefixes.
 *  </p>
 *
 *  <p>
 *  A <code>NamespaceContext</code> is responsible for
 *  translating prefixes as they appear in XPath expressions
 *  into URIs for comparison.  A document's prefixes are
 *  resolved internal to the document based upon its own
 *  namespace nodes.
 *  </p>
 *
 *  @see BaseXPath
 *  @see Navigator#getElementNamespaceUri
 *  @see Navigator#getAttributeNamespaceUri
 *
 *  @author <a href="mailto:bob@werken.com">bob mcwhirter</a>
 */
public interface NamespaceContext
{
    /** Translate the provided namespace prefix into 
     *  the matching bound namespace URI.
     *
     *  <p>
     *  In XPath, there is no such thing as a 'default namespace'.
     *  The empty prefix <b>always</b> resolves to the empty
     *  namespace URI.
     *  </p>
     *
     *  @param prefix The namespace prefix to resolve.
     *
     *  @return The namespace URI matching the prefix.
     */
    String translateNamespacePrefixToUri(String prefix);
}
